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Poster: JeffT Date: Feb 22, 2009 10:14pm
Forum: movies Subject: Problem with sound-video synchronization

The following item (nutritional talk by Dr. Michael Greger) has severe sound synchronization problems when played back using the flash player.
http://www.archive.org/details/sfvs_2009_02_15_Michael_Greger1
Symptom is that after a while the video lags behind the sound. Moving the position of the slider on the player will cause it to re-sync, but then the sound slowly gets out of sync again.
I think the problem is likely in the flash player, since the information syncing the sounds must be available the file (since it resyncs when the slider is moved), yet the player makes it unsynced when playing back continuously.
Lots of content I've uploaded seems to have this problem.

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Poster: Administrator, Curator, or Stafftracey pooh Date: Apr 14, 2009 11:37pm
Forum: movies Subject: Re: Problem with sound-video synchronization

trying a rederive of the video now with our updated deriver...

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Poster: JeffT Date: Apr 24, 2009 3:21pm
Forum: movies Subject: Re: Problem with sound-video synchronization

For testing, I created a new item (with the same source file) so I could compare the new derivations with the previous ones.

For some reason, the new item is not deriving. It's been "Waiting for admin" for the last 6 days.

Can someone please start the derivation, or tell me what I need to do to get it started. Item URL is:
http://www.archive.org/details/sfvs_2009_02_15_Michael_Greger1a

Thanks,
-Jeff Teeters

p.s. I first tried to rederive the original item, but nothing new was generated. I think I need to first remove the old derived files. I decided that making a new item would allow a better test since it allows both the previous and new derives to be viewed.

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Poster: Administrator, Curator, or Stafftracey pooh Date: Apr 27, 2009 2:46pm
Forum: movies Subject: Re: Problem with sound-video synchronization

hi there,
ok, the video processes, but the audio does not.
it's hard to get a lot of insight into the AAC track (like if it's got some strange multi-tracks in it or otherwise) but it *looks* like one or more of the timecodes w/i the AAC track are "wrong", per our ffmpeg tool.

Input #0, mov,mp4,m4a,3gp,3g2,mj2, from '/home/tracey/public_html/_/sfvs_2009_02_15_Michael_Greger1a/sfvs_2009_02_15_Michael_Greger1a.mp4':
Duration: 00:58:46.08, start: 0.000000, bitrate: 9130 kb/s
Stream #0.0(eng): Video: h264, yuv420p, 1280x720, PAR 1:1 DAR 16:9, 29.97 tbr, 29.97 tbn, 59.94 tbc
Stream #0.1(eng): Audio: aac, 48000 Hz, stereo, s16
Output #0, adts, to 'temp.aac':
Stream #0.0(eng): Audio: libfaac, 48000 Hz, stereo, s16
Stream mapping:
Stream #0.1 -> #0.0
Press [q] to stop encoding
[NULL @ 0x8081380]error, non monotone timestamps 317337810 >= 317337810
av_interleaved_write_frame(): Error while opening file


the "non monotone timestamps" means that every audio frame should be increasing in timestamp, but at least one did not.

anyway you could try to get us an updated AAC audio track for the video?
i could splice/replace it into your existing video if that works so you can avoid re-exporting and uploading the full 3.4G video?

--tracey

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Poster: JeffT Date: Apr 28, 2009 9:46am
Forum: movies Subject: Re: Problem with sound-video synchronization

I thought the problem might be that the file got corrupted on upload, so I made yet a new item, but it seems to fail also.
http://www.archive.org/details/sfvs_2009_02_15_Michael_Greger1b
Now I noticed that I'm getting the same problem on another video I just uploaded:
http://www.archive.org/details/ucb_physics_2009_04_27_Mike_DeWeese

Both of these videos were recorded using an Xacti 1010 (mpeg4 avc/h.264 format), with settings: 30fps, 720P resolution. I thought the problem might be due to the fact that these videos were formed by merging two shorter videos. Details: Since both videos were over an hour long, and one hour takes up the maximum file size in the flash memory (4GB) the Xacti splits the video into two files: the first 4GB, then the rest. I merge these two parts using a program called "MPEG StreamClip" which runs on a Mac. I thought the problem might be due to MPEG StreamClip not changing the audio count when merging the second clip. To test this I made two small (10 second) clips and merged them using MPEG StreamClip; but the resulting file derived fine.
http://www.archive.org/details/streamclip_merge_test_2009_04_28
So it looks like that's not the problem.

Other videos I've uploaded that were shorter than 4GB seemed to work with the new derivation, although in the generated thumbnails some black areas include strange white speckles, that I've never seen before. But otherwise these are good in that in the derived video is OK and the audio and video seem to be synced. Examples are:
http://www.archive.org/details/Redwood_Center_2009_04_22_Thomas_Serre
http://www.archive.org/details/ucb_calday_2009_04_18_George_Brimhall

So I'm not sure what the problem is. Perhaps archive.org is using a new version of ffmpeg, and there is a problem with the files that was tolerated using the old version but which is not in the new version.

I do see that others have been puzzled by this error. For example:
http://forum.videohelp.com/topic336168.html

When I get time, I may try to find a program that can check the files I'm uploading for errors or install ffmpeg and see if I can reproduce the error and find a solution. But anything you can do or suggestions you have will be much appreciated.


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Poster: Administrator, Curator, or Stafftracey pooh Date: Aug 27, 2009 11:12pm
Forum: movies Subject: Re: Problem with sound-video synchronization

ok, basically a few developments and notes.

1) looks like all the items you mentioned that *did* seem to to make our h.264 derivatives *and* had good A/V sync were using our current ffmpeg version tool (we rebuilt it right after a big ffmpeg release (v 0.5) in march)

2) we have another video from someone we work with regularly that is having similar issues (timestamps being same for 2+ frames, at least per ffmpeg). i tried once again to see if i could patch ffmpeg (didn't seem to work before) and this time, with more persistence, i was able to make my original fix idea work. his video has A/V sync issues, but at least it derived (his may have had some minor A/V sync issues on input, but we clearly made them much worse)

anyway, so i'm trying in the background your video again to see if i get any different results...
-tracey

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Poster: JeffT Date: Aug 28, 2009 1:14pm
Forum: movies Subject: Re: Problem with sound-video synchronization

Thanks Tracey for all of your work on this! That would be awesome if you are able to get the sound and video to synchronize consistently in the derived videos. Please do let us know what you figure out.

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Poster: Administrator, Curator, or Stafftracey pooh Date: Sep 3, 2009 5:13pm
Forum: movies Subject: Re: Problem with sound-video synchronization

hi jeff,

ok, this derived fine now that i was able to get my fix/workaround live:

http://www.archive.org/details/sfvs_2009_02_15_Michael_Greger1a

i am deriving these items, too, now:
PS1_Longplay_Mortal_Kombat_Mythologies_Sub_Zero
sfvs_2009_02_15_Michael_Greger1
sfvs_2009_02_15_Michael_Greger1b
ucb_physics_2009_04_27_Mike_DeWeese
VideoEditingWithChris-001

--tracey

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Poster: JeffT Date: Sep 4, 2009 11:33am
Forum: movies Subject: Re: Problem with sound-video synchronization

Thanks Tracey!
Here are two more videos that might be good to test. Both were derived a long time ago (Nov. 2008). First worked. The second had terrible sound synchronization problems. Or if you prefer, I can re-derive them and let you know.

Worked:
Sanyo Xacti HD 1010 TVHR mode.
http://www.archive.org/details/sanyo1010tvhr-test_2008_09_23a

Failed:
Sanyo Xacti HD, TV-SHQ mode.
http://www.archive.org/details/sanyo1010tvshq-clock-test-h264

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Poster: Administrator, Curator, or Stafftracey pooh Date: Sep 4, 2009 2:20pm
Forum: movies Subject: Re: Problem with sound-video synchronization

think we are good there now on the 2nd video w/ our updated deriver! 8-)
w/ similar fix, i can make the "ogg video" now, too, yay (will get the ogg video fix live very soon).

so in related news, a rederive of this one
http://www.archive.org/details/ucb_physics_2009_04_27_Mike_DeWeese

still has unacceptable A/V sync drift/issues.
but check this out (from the derive.php log)

# [mov,mp4,m4a,3gp,3g2,mj2 @ 0x8075f00]multiple edit list entries, a/v desync might occur, patch welcome


so i'm not entirely sure how that relates to what might have been done
make this video, but it seems that ffmpeg is at least aware that something
in the way of the source might have issues...

anything less typical than your other vids/tests come to mind for this one?

--tracey

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Poster: JeffT Date: Sep 8, 2009 1:54pm
Forum: movies Subject: Re: Problem with sound-video synchronization

Hi Tracey,
I don't recall anything unusual about the recording and processing of the Mike DeWeese video. Thanks again for all your work on this.
-Jeff



This post was modified by JeffT on 2009-09-08 20:54:27

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Poster: Administrator, Curator, or Stafftracey pooh Date: Aug 29, 2009 12:09pm
Forum: movies Subject: Re: Problem with sound-video synchronization

hi jeff,

ok some news...
got a prior test item of yours (that was unable to make any derivs at all previously -- with the ffmpeg that was before the major v0.5 release in march) to make all 4 derivatives, woot. (prior ffmpeg versions could
not decode AVCHD)

http://www.archive.org/details/canon-hf-10-test-2008_09_23a

that's with the normal ubuntu (jaunty) ffmeg.
i got one of your sfvs videos (offline) to derive with a small fix/workaround to ffmpeg and tried to redo a bunch of your live items (but they didn't work out) so i'm trying to figure out what that minor issue is and redo your live items...)
(and sfvs_2009_02_15_Michael_Greger1a did seem to come out fine in testing offline w.r.t. A/V sync so things are looking up at least 8-)

more as i know it...
--tracey

PS: if you know of other h.264 source video that i should try my fix (when i get it fully working enough to run on "live items") other than these:
PS1_Longplay_Mortal_Kombat_Mythologies_Sub_Zero
sfvs_2009_02_15_Michael_Greger1a
sfvs_2009_02_15_Michael_Greger1b
ucb_physics_2009_04_27_Mike_DeWeese
VideoEditingWithChris-001
feel free to let me know! (i think they all had similar issues)





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Poster: Administrator, Curator, or Stafftracey pooh Date: Apr 28, 2009 3:51pm
Forum: movies Subject: Re: Problem with sound-video synchronization

basically it's the fact that there seem to be two adjacent audio frames w/ the same timestamp. the new ffmpeg doesn't like that so entire deriving of our h.264 mp4 fails. our prior ffmpeg could handle the audio, so i may look into the source code to see what happens if we allow audio frames w/ same timestamp to not fatal...

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Poster: Administrator, Curator, or Stafftracey pooh Date: Apr 24, 2009 3:37pm
Forum: movies Subject: Re: Problem with sound-video synchronization

hi there,
yes i've been trying to see if i can construct a workaround for you video
(sorry for the delay). i may have something now and am trying it "offline"
first to see if it works / is better.

-tracey, storage engineer, webmaster, video geek 8-)

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Poster: billbarstad Date: May 6, 2009 5:22am
Forum: movies Subject: Re: Problem with sound-video synchronization

I see the same problem with this movie trailer.

What happened to the 'Report errors' link on item pages?